Should be 11mpbs. I *heard* that the 22/44 multiband ones aren't as impressive as they sound - works when yur right next to the box, but significant drop offs as you move away. And as skyking mentioned, unless you're serving files, or streaming something, it should matter - and if you do decide to do that, I'd recommend hard wired connection.
I like the Dell Truemobile 1150(?) for my laptop. Suppose to be rebadged Orinoco Gold - dunno if you need to flash it to make it so, or not (I haven't tried). My brother uses this combo, but he says his signal gets low in other rooms. Anyone else experience this? He lives in an apartment complex, so I assume it's 'cuz they have thick walls lined with lead or something - I think it works fine through normal walls. You can probably get the card for $45 from Dell when it's on sale. Great price for an excellent card.
If you need a card for a desktop system, I'd recommend a USB thing, with an external transmitter that can sit on your desk. My understanding is the chassis interferes with the signal, so having the transmitter on your desk is better.